Abstract
A thermal engineering class design project involving friction calorimeter apparatuses that produce Joule's constant is described. The class assignment required design and construction of equipment, trial-and-error experimentation, and data reduction to obtain the relationship between work and heat given by Joule's constant (J = 778 (ft lbf)/Btu). The student's designs used falling weights, rotating flywheels, and swinging pendulums that produced rubbing friction on a small piece of copper that acted as a calorimeter. The author's design employed a bicycle with a copper calorimeter friction brake on the front tyre. Heat loss into the rubber tyre was analysed. Also, aerodynamic drag and rolling friction were analysed using bicycle coast-down data. The combined results from eleven different student designs yielded an average Joule's constant that was 32% high. The author obtained a Joule's constant that was 16% high.
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